Oil compositions having reduced foaming tendencies



OIL COMPGSITIONS HAVING REDUCED FQAMING TENDENCIES Norman E. Delfel, Scotch Plains, N.J., assignor to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Aug. 6, 1957, Ser. No. 676,508 2 Claims. c1. zs2-3s.4

This invention relates to foam inhibition of oil compositions. Particularly, it relates to the inhibition of foaming by mineral oil compositions containing additives such as lubricating oils, hydraulic oils and the like may 25 cause operating difiiculties in machinery as well as in the processing of the oils themselves. Oil additive materials, which are desirable because they prevent sludging, deposition of gum and the like, are frequently strong foam promoters and the modern tendency to use such materials in increasing quantities gives rise to increasing difficulties with foaming. It had been proposed to use a silicone polymer to inhibit foaming of such compositions. However, generally, the silicones either will not suppress foaming or, if they initially do suppress foaming, they lose their effectiveness upon standing. It has now been found that the effectiveness of silicone polymers as anti- -foamants in certain oil blends can be materially increased and enhanced by use of hydrocarbon compounds having a single polar group at the end of the molecule. The use of these latter materials, in conjunction with the silicones, increases the initial effectiveness of the siliconeand also gives increased foam stability, that is, there is ing. This combination is much more effective than either the silicone or the polar material alone. It has further been found that the effectiveness of these 'materials can be even further increased by heating the oil composition containing the silicone and the polarjmaterial.

In general, the heavier the hydrocarbon 'oil and the tendency to foam and the more difiicult to inhibit its foaming. Additives such as the oil-soluble sulfonates; the salts of alkylated aromatic compounds such as: alkyl phenols, alkyl phenol sulfides, and the phosphorus sulfide treated derivatives of such materials; and the like, fre-" quently tend to promote foaming in conventional mineral base hydrocarbon oils. I

According to the present invention, additives of the above types and various mixtures of such' additives are treated, preferably in oil solution, with 0.001 to 1.000, e.g. 0.01 -to 0.20. weight percent of a silicone and about 0.03 to 15.0, e.g. 0.5 to 15, weight percent of a polar material, said weight percentages being based on the weight of, dry additive.

of silicone, polar material and detergent concentrate may be heated sufficiently to melt the. polar material'so as to obtain a homogeneous mixture after agitation.

1 This treatment may be carried out by simply mixing the silicone and polar material into The method of the present invention is particularly effective in reducing the foam-promoting tendencies of metal sulfonates, metal alkyl phenol sulfides, and mixtures thereof. These particular compounds are well 5 known to the art as detergent additives for lubricating oils, particularly mineral lubricating oils, and are generally employed in the form of alkaline earth metal salts (the sulfonates are frequently also employed in the form of alkali metal salts).

These metal sulfonates are oil-soluble salts of high molecular weight sulfonic acids which are generally produced by the treatment of petroleum oils of the lubricating oil range with fuming sulfuric acid. The sulfonic acids which are employed in the production of lubrieating oil additives have molecular weights of about 350 to 650, frequently of about 400 to 550. These petroleum sulfonates have been described in numerous patents as, for example, U.S. 2,467,176. The sulfonates can also be derived from relatively pure sulfonic acids having from about 10 to 33 carbon atoms per molecule.

For example, sulfonated products of alkylated aromatics such as benzene, toluene, xylene, etc., alkylated with olefinsor olefin polymers of the type of polypropylene, polyisobutylene, etc. can be used. Specific examples of such sulfonates include: calcium petroleum sulfonate, barium petroleum sulfonate, sodium petroleum sulfonate, calcium C alkyl benzene sulfonate, barium C alkyl benzene sulfonate, sodium C alkyl benzene sulfonate, etc.

" The metalalkyl phenol sulfides and polymers thereof used as oil additives and their preparation are also well known to the art and havebeen described in numerous patents, as for example, U.S. 2,451,345 and U.S. 2,362,289. .These materials have the general formula:

wherein. M represents a metal such as aluminum, cobalt,

chromium, magnesium, sodium, lead, tin, etc., or the ..alkaline earth metals as calcium, barium, strontium, etc. (in the case of polyvalent metals, the other valences of the metal may be joined to other inorganic or organic groups or to another alkyl phenol sulfide group), ,RlS generally an alkyl group of 5 to 20, e.g. 8 to 10 carbon atoms,.R' is an aryl, alkyl, araIkyLJaIkyI-aryl radical, etc., or another alkyl phenol sulfide group, while x is'a number about 1 to 5. Specific examples of these materials include barium tertiary octyl phenol sulfide, cal- V i cium tertiary'octyl phenol sulfide, barium-calciumtergreater its content of additive, the greater will be its' tiary octyl phenol sulfide, barium tertiary. amyl phenol sulfide, calcium tertiary amyl phenol sulfide, barium nonyl phenol sulfide,"etc. Mixtures of metal sulfonates with metal alkyl phenol sulfides in proportions of about 5 to 95% by weightQpreferably about 10 to 50% by weight, of the metal sulfonate, are frequently employed in lubricating oil compositions.

Silicones which may be used are the dimethyl silicones of the general formula:

wherein n is a number of about 0 to 100,000, e.g. 100

to 900. These silicone polymers will generally have viscosities of 0.65 to 60,000 cs., e.g. 100 to 12,500 cs. at 25 C. depending upon the molecular weight. A 'preferred silicone oil is Dow Corning Fluid 200, which has a viscosity at 25 C. of about 1,000 es. and is a dimethyl polysiloxane. Other silicones having longer alkyl groups "or aryl groups attached to the silicon atoms'do' not and the polar material mixture may then be heated to temperatures of about 100 have the same effectiveness as the dimethyl silicones in the compositions of the invention.

The polar materials which may be used include those 'Cyto C e.g.,-C to C aliphatic hydrocarbons, saturrated"or'unsaturated, straight chain or branched chain which at the end-of the molecule are substituted with a single polar group such as -OH, --CHO, -COOH, --NH and SH groups. Those materials having 16 to-40-carbon atoms in the chain are particularly preferred .as they are more effective than the shorter chain mate- .rials. Specific examples of these materials include alcohols such as: hexadecanol-1, octadecyl alcohol, docowhich may be used are the Oxo alcohols, which are isomericrnixtures of highly branched chain primary alco- 2110.18. These alcohols are prepared from olefins, such -as polymers and copolymers of C and C monoolefins,

which are reacted with carbon monoxide and hydrogen,

in the presence of a cobalt-containing catalyst such as a cobalt carbonyl catalyst, at temperatures of about 300 to 400 F., and pressures of about 1000 to 3000 p.s.i. to

form aldehydes. The resulting aldehyde product is then hydrogenated to form the alcohol which is recovered from the hydrogenation product.

The treatment of the foam-producing detergent additives with silicone and the polar material, in accordance with this invention, is preferably carried out with the additives in the form of additive concentrates. Generally, these additive concentrates will contain about to 70%, e.g., to 50% by weight of the dry additive. The remainder of the concentrate will be. predominantly a diluent oil such as a mineral lubricating oil, in which the detergent additives aresoluble. In certain instances, the

additive concentrate may contain minorproportions of other additives such as antioxidants, viscosity index improvers, and the like. After the addition of the silicone to the additive concentrate, the

to 500 F., e.g., 150 to 300 F., for about 10 minutes to 5 days, e.g., 1 to 24 hours. has been found that the heating generally gives .better results. Ifa lower temperature is used, then a longer time of heating is desirable.

For example, it has been found that treatment at 300 F. forabout A hour is about equivalent to treating at 140 F. for about 48 hours.

The invention is further illustrated by the following examples whichinclude preferred embodimentsof the invention.

. -EXAMPLE1 a A series of tests were conducted usingabase ,oil composition of 9.0 weight percent, .basedon the weight of the total composition,

of a detergent additive concentrate in :91 weight percent of mineral lubricating oil'(SAE 50 grade). The additive concentrate consisted of: (1) about by weight of a mineral oil (lubricatingyviscosity) solution wntaining as the active ingredient-.about 35%:by weight of a barium nonyl phenol sulfide havinga sulfur to barium ratio (weightlbasis) of about 0.37 and (2) about 35% by weight of a mineral-oil (lubricating vis-. cosity) solution containing as the active ingredient about. 35% by weight of calcium synthetic sulfonate made from sulfonation of alkylated benzene. This calcium sulfonate, had a molecularweight ranging from 780 to 1120 and an "average molecular weight ,of about 912. The abovebase composition was treated without heating with silicone ,alone and'the polar material alone and'then variouscom- -binations of the silicone oil plus thepolar material. These various compositions were tested for foam-tendericy (cc. ot foamafter 5 minutes aeration) and foam stability. (cc. ;.of foam volume after 10 minutes settling), according to ithe .A.S.T. M foam test, Q8 9 2 -,4 6T. The; results-pf the weight of. dry additive.

-Although not essential, it

these tests are summarized in the following table wherein FT stands for foaming tendency and PS for foam stability and all weight percents are based on the weight of the dry additive.

Table 1 Amount of Stabilirer (Based on Weight of Initial, 2 Weeks Dry Additive) FT/FS Storage,

FT/FS Non 600/550 610/580 5.70% l-octadecanol 1 480/33) 11.40% l-octariecanol. 250/30 280/20 0.029% dimethyl silicone oil 590/390 640/560 0.058% dimethyl silicone oil 440/280 580/560 5.70% l-octadeeanol and 0.029% dimethyl silicone oil 40/0 50/0 1 Sold under the trade name Lorol 28." Dow Corning 200 Fluid, 350 cs. (25 0.) grade.

As seen from the above data, using either the l-octadecanolor silicone alone had little effect upon decreasing .the foaming of-the composition. However, when both the alcohol and silicone were used together the foaming tendency and foam stability were markedly improved.

EXAMPLE 2 A series of tests were run similar to that of Example 1, except that various other polar materials in varying percentages were added to the detergent-containing base oil,

and a different grade of dimethyl silicone was used. In each case, after the addition of the polar material, the oil composition .was then heated to 300 F. for 10 minutes, then cooled and tested. Results of these tests are summarized in the following table where the weight percent- 1 ages are'basedon the weight of the dry detergent additive. i

Table II Foam Level Percent Percent .Bolar Material Added Silicone Run I to Base Oil Added Stored to Base Initial, (14

Oil FT/FS Days), FT/FS None 0. 085 360/50 560/480 3.2% l-Octadeeanol (Lorol28).-- 0.085 3 0 50/0 6.4% I-Octadecanol (Lorol 28) 0. 085 40/0 50/0 12.8% l-Oeta'decauol (Lorol 28).. 0. 085 60/20 60/20 I 12.8% 013 Oxo'Alcohol 0.085 240/10 320/10 12.8% 0 3 0x0 Alcohol. 0.085 220/10 350/20 6.4% C 0x0 Acid. 0. 085 /0 280/5 6.4% 0 0X0 Aldehyde- 0. 085 190/10 250/0 6.4% Cu Lorol Mercaptan" 0.085 120/5 90/30 iBase oil was the same as used in Example 1, i.e., containing the 9 weight percent of detergent concentrate. f J DowCorning Fluid 200, 1000 cs. (25 C).

- As seen non Table II, the combination of the silicone and polar materials improved both the initial and stored foaming tendency and foam stability. The best improvement, however, was achievedby use of the longer chain ;octadecanol asvcompared'to the shorter chain polar material." Runs 4-.and 5 were duplicate runs to show the repro uc b it of the resu e t o g t ts- I EXAMPLE In gTo further jillustrate the. invention, another series of tests werejmade sirnilar to the manner of Example I, vusing stearieacid as thepolarv material, with and-Without .fheating. .Theresults of these-tests are summarized in Table ,I-II whereall. of said weight percents are based on 1 Base oil similar to that of Example I but of a difierent batch. The base oil consisted of 91 weight percent mineral oil and 9.0 weight percent of additive concentrate of barium nonyl phenol sulfide and calcium synthetic sulionate.

fl Dimethyl silicone-DO-200 fiuid, 1000 cs. (25 C.) Grade.

Heated for 15 minutes at 300 F., then cooled and tested for FT/FS As seen from Table III, heating the base oil had only a slight effect on decreasing the foaming (see runs 1 and 2). The use of the silicone alone, withand' without heating, resulted in a slightly further improvement (see runs 3 to 6). The use of the acid alone, both with and without heating, again showed only a slight improvement (runs 7 to 10). However, when both the acid and silicone (run 11) were added to the base oil a very pronounced reduction in the foaming level was obtained, and when this mixture was then heated (run 12), the foaming was completely eliminated.

In summary, the invention relates to the foam inhibisaid oils a mixture of a dimethyl silicon oil and a polar 6 material of the general formula: RX, where R is an aliphatic hydrocarbon radical (e.g. an alkyl radical), and X is a radical such as OH, CHO, COOH, NH and -S1-I, and which may or may not be followed by heating.

. What is claimed is:

1. An improved mineral oil composition having a decreased foaming tendency consisting essentially of a major proportion of mineral oil and a minor amount of an oil-soluble detergent additive selected from the group consisting of metal sulfonates, metal alkyl phenol sulfides and mixtures thereof, about 0.001 to 1.000 gram of a dimethyl silicone polymer per grams of dry additive and about 0.03 to 15 grams per 100 grams of dry additive of l-octadecanol, said dimethyl silicone polymer having a viscosity at 25 C. in the range of 100 to 12,500 cs.

2. The mineral oil composition of claim 1 wherein the amount of silicone polymer used is about 0.01 to 0.20 gram per 100 grams of dry additive and the amount of l-octadecanol used is about 0.5 to 15.0 grams per 100 grams of dry additive.

References Cited in the file of this patent UNITED STATES PATENTS 2,430,858 Borsofl' et al. Nov. 18, 1947 2,533,700 Wallace Dec. 12, 1950 2,563,588 Dixon Aug. 7, 1951 2,761,845 Rogers et al. Sept. 4, 1956 2,790,768 McCoy Apr. 30, 1957 FOREIGN PATENTS 585,803 Great Britain Feb. 25, 1947 666,239 Great Britain Feb. 6, 1952 

1. AN IMPROVED MINERAL OIL COMPOSITION HAVING A DECREASED FOAMING TENDENCY CONSISTING ESSENTIALLY OF A MAJOR PROPORTION OF MINERAL OIL AND A MINOR AMOUNT OF AN OIL-SOLUBLE DETERGENT ADDITIVE SELECTED FROM THE GROUP CONSISTING OF METAL SULFONATES, METAL ALKYL PHENOL SULFIDES AND MIXTURES THEREOF, ABOUT 0.001 TO 1.000 GRAM OF A DIMETHYL SILICONE POLYMER PER 100 GRAMS OF DRY ADDITIVE AND ABOUT 0.03 TO 15 GRAMS PER 100 GRAMS OF DRY ADDITIVE OF 1-OCTADECANOL, SAID DIMETHYL SILICONE POLYMER HAVING A VISCOSITY AT 25*C. IN THE RANGE OF 100 TO 12,500 CS. 